Truck trailers used for transporting freight include both open and closed bed trailers. Open bed trailers, commonly referred to as flatbed vehicles, offer the advantage of accommodating a variety of loads and are generally less expensive to produce. Further, the load on the trailer can be accessed from the sides and above as well as from the rear of the vehicle. However, these trailers have disadvantages in that the load is open to the environment and can be damaged in transit or readily pilfered. Further, it is not particle to transport certain types of cargo on an open bed trailer, especially during inclement weather.
Closed trailers have the advantage of providing superior protection and security for the load. However, the presence of a conventional enclosure with a fixed height roof limits access to the load, makes loading of the trailer more difficult, and results in less useable space for the same size trailer bed width and limits the use of forklifts to load the trailer as the trailer roof interferes with the ability of the forklift operator to adequately lift the load. Further, the mere presence of the walls and roof of the enclosure limits the ability to utilize the full internal width and height of the enclosed trailer without hand stacking.
In addition, in order to accommodate all types of freight, a carrier must maintain an inventory of both open and closed trailers. Inventory requirements could be reduced by a truck trailer that can be easily loaded from the sides or from overhead, as with a conventional flatbed trailer, yet have an enclosure that provides added protection and security for the load.
Open trailers are typically utilized for transporting crushed vehicle bodies, since there is not any practical method for quickly and easily loading a crushed vehicle body onto a covered trailer. However, new Federal laws require that crushed autobodies transported on a trailer are covered to prevent any loose debris from falling from the trailer onto the roadway. Conventional methods of covering crushed automobiles (or other cargo) involve placing a tarp over the cargo. This is often very difficult and may subject operators to injury due to falls while placing the tarp.
U.S. Pat. No. 6,017,082 describes a truck trailer body system with movable enclosure sections, which are preferably slidingly nestable canopies. The canopies are positionable for completely enclosing and protecting cargo from environmental damage during transportation or storage, and also for selectively providing unfettered access to areas of the trailer bed for loading and unloading.
U.S. Pat. No. 6,196,604 describes a removable enclosure for a flatbed vehicle. The enclosure comprises a panel roof supported by four upright supports for removably mounting on an open bed trailer. Two upright supports are located on the left and right corners (the driver side and passenger side) of the forward edge of the trailer, and the other two uprights are located at the rear corners of the trailer. Two movable and removable side supports typically are used with the disclosed enclosure. Elevating means within the upright supports allow the front and/or rear portions of the roof to be raised and lowered separately. Using external attachable fixtures and ground mounted supports, each of the roof supports can be lifted from their mounted position on the trailer bed and the trailer can be driven out from under the supports and roof assembly, converting a covered van to a fully open van. A tarpaulin, or other readily removable wall materials, can be suspended from the roof and attached to the trailer bed.
U.S. Pat. No. 6,196,786 discloses a cargo transporting vehicle having a flap unit mounted as a cargo containing unit on a flatbed trailer so that it can be freely moved along the longitudinal direction of the truck. The flap unit comprises pillars that form the framework for the cargo containing unit. Each of the pillars includes an upper wheel and a lower wheel that sandwich a flange of an I-beam member. This arrangement allows the pillars to be moved along the length of the trailer to cover or uncover the trailer bed. Side panels which form the sidewalls of the trailer cover, and roof panels are hinged to the pillars so that they can be folded or swung into a position that allows the pillars to be rolled forward toward the front of the trailer to uncover the flatbed.
Other patent publications that address similar issues include U.S. Pat. Nos. 5,282,663; 3,266,837; 3,252,730; 3,155,419; 2,974,996 and 2,866,663.